The present invention relates to a projector lens system of a projector apparatus.
Japanese Laid-Open Patent Publication No. 2001-116990 discloses a projector lens that is bright with an F number of around 2.4, has high resolving power in spite of having a wide angle of view with a half angle of at least 45 degrees, has a sufficiently long back focus for the provision of a color synthesizing means, and has favorable telemetric characteristics. To do so, the projection lens in Publication No. 2001-116990 is constructed, from the enlarging side to the reducing side, of a first lens group I with negative refractive power, a second lens group II with positive refractive power, and a third lens group III with positive refractive power, with a comparatively long spacing provided between the first lens group I and the second lens group II, the first lens group I entirely composed of negative lenses, and the lens that is closest to the reducing side out of the lens group I having an aspherical surface.